Go with the NRS from what I have heard... Either is going to be fine, but the Teva hasn't been holding up from what I hear.
That boat fits your body size perfect (unless your torso is a foot tall and legs are 40+ inches HA).
You should be able to fit perfectly in the middle seat position. You may need to shave the foam down a bit, but even then, that shouldn't be a problem.
As mentioned above if you are new, you may not understand the importance of a tight fit yet. It can be a bit strange for newbies. Makes you feel cramped, but you want tight. What you don't want is uncomfy, and it would be odd if you were not comfy in a jackson, it's what we pride our brand on, and i'd be surprised if the problem isn't a bit of just getting used to a small kayak.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body. But rather...To skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming... WOW !!!! What a ride!!!!!!"